Bug 1427984 (CVE-2017-6347)

Summary:	CVE-2017-6347 kernel: ipv4: Incorrect IP_CHECKSUM handling
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	aquini, bhu, dhoward, fhrbata, gansalmon, hwkernel-mgr, iboverma, ichavero, itamar, jforbes, jkacur, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, lgoncalv, madhu.chinakonda, mchehab, mcressma, nmurray, pholasek, rt-maint, rvrbovsk, vdronov, williams, wmealing, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	The skbs processed by ip_cmsg_recv() are not guaranteed to be linear (e.g. when sending UDP packets over loopback with MSGMORE). Using csum_partial() on potentially the whole skb len is dangerous; instead be on the safe side and use skb_checksum(). This may lead to an infoleak as the kernel memory may be checksummed and sent as part of the packet.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-10-27 10:52:09 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1442927, 1442944
Bug Blocks:	1427985

Description Andrej Nemec 2017-03-01 16:14:44 UTC

The skbs processed by ip_cmsg_recv() are not guaranteed to be linear e.g. when sending UDP packets over loopback with MSGMORE. Using csum_partial() on [potentially] the whole skb len is dangerous; instead be on the safe side and use skb_checksum().

Upstream patch:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ca4ef4574f1ee5252e2cd365f8f5d5bafd048f32

References:

http://seclists.org/oss-sec/2017/q1/525

Comment 1 Fedora Update System 2017-03-03 03:50:18 UTC

kernel-4.9.13-100.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.

Comment 2 Wade Mealing 2017-03-27 05:27:07 UTC

Statement:

This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 4,5,6,7 and MRG-2.

Comment 4 Wade Mealing 2017-03-27 05:31:26 UTC

Upstream patch:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ca4ef4574f1ee5252e2cd365f8f5d5bafd048f32

CVE-Request:

http://seclists.org/oss-sec/2017/q1/525

Comment 5 Wade Mealing 2017-04-18 06:07:05 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1442927]

Comment 7 Justin M. Forbes 2017-04-18 12:40:53 UTC

This was fixed upstream in 4.10.1.  The fix was pushed to Fedora 25 with the 4.10.5 rebase on 3-27 and in Fedora 24 with the 4.10.6 rebase on 4-01.